This kind of conventional electrolytic capacitor has been constituted as shown in FIG. 1. That is, capacitor element 1 made by winding an anode foil and a cathode foil together with a separator and soaking with an electrolyte for operation is enclosed in a metal case which is of a cylindrical shape having a bottom, open end of which is sealed with a terminal plate 3; and mounting on a printed circuit substrate is made with terminals 4 by electrically and mechanically connecting and fixing them.
Furthermore, recently a snap-in type terminal configuration has been proposed as shown in FIG. 2. This kind of electrolytic capacitor has terminals 5 of curved shape and furthermore, end tip of them are narrow, thereby making insertion on the printed circuit substrate easy.
The electrolytic capacitor has polarity as is well known, and in case it is mounted with wrong polarity not only function as the electrolytic capacitor is not achieved but also there is a danger of fire, and the opposite insertion must be practically nil. Therefore, hitherto indicating part 6 is provided on an outside sleeve or indication has been made on rivets 7 for fixing terminal.
In such case, polarity confirming of the electrolytic capacitor must be made by eye, and in actual mounting operation sometimes mounting errors (opposite insertion) occur thereby inducing unexpected accidents.
Furthermore, since such kind of electrolytic capacitor is larger in size and more heavy in weight in comparison with other electronic components, when it is mounted on a printed circuit substrate and the apparatus is vibrated, effect on the printed circuit substrate centers around terminal parts of the electrolytic capacitor and peeling off of copper foil of the printed circuit substrate or the like has happened.
Furthermore, in actual mounting operation, such kind of aluminum electrolytic capacitor together with other electronic components are soldered, and thereafter to flux washing-out is carried out to remove pine resin. In such case, washing agent is retained in a gap between the printed circuit substrate and the electrolytic capacitor; and since the washing agent is constituted with organic chrolide compound, it has become a cause to make corrosion defect of the aluminum electrolytic capacitor.